docs: def simple_parse_file(filename: str) -> Feed:
      """Parse an Atom, RSS or JSON feed from a local file."""
      pairs = (
          (rss.parse_rss_file, _adapt_rss_channel),
          (atom.parse_atom_file, _adapt_atom_feed),
          (json_feed.parse_json_feed_file, _adapt_json_feed)
      )
      return _simple_parse(pairs, filename)